Lid seal for shipping containers



.1.H. scHuRlNGA LID SEAL FOR SHIPPING CONTAINERS Sept. 17, 1968 `Filed Sept. 22, 1967 I r' stuw E ON Q`\\ .V/I//IZV/IN.. mm SS N NN ArTYs.

United States Patent O 3,401,864 LID SEAL FOR SHIPPING CONTAINERS Jan Harm Schuringa, Badhoevedorp, Netherlands, assignor to Inland Steel Company, Chicago, Ill., a corporation of Delaware Filed Sept. 22, 1967, Ser. No. 669,751 Clailns priority, application Great Britain, Sept. 29, 1966, 43,664/ 66 8 Claims. (Cl. 229-57) ABSTRACT F THE DISCLOSURE A cover closure for shipping containers is described in which a separate inner member forms a resilient peripheral lip which presses against a corresponding internal circumferential rib of the container body to effect a seal.

Description of the invention This invention relates to shipping containers. In particular, it relates to shipping containers of the type made of brous material such as kraft paper, paperboard, cardboard and similar materials. In its principal aspects it relates to such a container in which the container body has an open end and a chime which includes an internal circumferential rib adjacent the open end.

Such shipping containers must be capable of being securely closed by a cover or lid to contain their contents. The cover may be of sheet metal, libre, Wood or other suitable material. However, it is often necessary that the content of the container be prevented from coming into contact with metal parts. This is true in the case of chemically active or aggressive commodities which would be contaminated by contact with metal, or which would weaken or corrode the metal portions of the container itself. Wood, such as plywood, is therefore sometimes used for the cover or lid, but this material also has certain disadvantages in this application since it is not easily formed into the shapes required. For this reason a paperboard cover or a cover made of easily formed plastic or brous materials is preferred.

Although paperboard or other fibrous material has obvious advantages in these applications, it has been found that an effective seal is often diiiicult to achieve with covers or lids made of these materials. Such a cover is generally made of a single layer of material formed with a circumferential rim or skirt which overlies the open end of the container and is crimped thereto by the application of a metal band or other suitable closing device. Because the line of contact between the open end of the container body and the cover is often irregular, leakage is sometimes experienced at this point. A metal rim or band is also occasionally used to reinforce the chime area of the container, and this band may be turned or rolled over so that a portion is exposed to the inside of the container body. If the container is used for transporting aggressive commodities a portion of the reinforcing band of the chime is thus exposed to the container contents with resultant deleterious effects.

In achieving a reliable seal in such containers, another difficulty is also experienced. This arises from the manufacturing operations which must be carried out in order to form the rolled rim or skirt which overlies the mouth of the container and against which the clamping ring or other closing apparatus is applied. In the case of covers made of fibrous materials, the rim or skirt is formed in the cover by rolling or other suitable forming operation, but such operations cannot be satisfactorily performed on material having too great a wall thickness. On the other hand, a substantial wall thickness is necessary in the f a 3,401,864 Ice Patented Sept. 17, 1968 linished cover so that the container will have the desired degree of rigidity and strength.

In view of the foregoing requirements, it is a principal object of the present invention to provide a closure assembly for shipping containers which is' capable of achieving an effective seal to prevent contact of the container contents with metal portions of the container, while still possessing advantages of strength and ease of fabrication. In one specific aspect, it is contemplated that the invention shall provide for the construction of strong, rigid container covers made of fibrous materials such as kraft paper, paperboard, cardboard and the like.

A more detailed object is to provide a shipping con tainer closure member which etects a seal in a relatively protected region of the shipping container which is spaced from the outermost portion of the container mouth. It is particularly contemplated that the seal will be effective against the internal portion of the chime area of the container whereby the crimping or clamping action of the cover member does not eifect the quality or the effectiveness of the seal. In greater particularity, it is contemplated that a peripheral lip seal will be provided which mates with an inner surface of the inturned circumferential rib of the container chime, and which may be further reinforced or clenched in place to provide a stiff yet resilient seal.

Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings, in which:

FIGURE 1 is a fragmentary cross-sectional elevation of a shipping container having a closure assembly constructed according to the present invention;

FIG. 2 is a rst alternative embodiment of the shipping container closure of FIG. l;

FIG. 3 is a second alternative embodiment of the shipping container closure of FIG. 1; and

FIG. 4 is a third alternative embodiment of the shipping container closure of FIG. 1.

While the invention will be described in connection with certain preferred embodiments, it Will be understood that it is not intended to so limit the invention, but it is instead intended to cover all alternative and equivalent constructions as may be included within the spirit and scope of the invention as defined by the appended claims.

Turning to the drawings, there is shown in FIG. 1 a cross-sectional View of the chime area and closure of a shipping container 11. In this embodiment the container is made of brous material, but it should be understood that a metallic container body can be used as well.

The container Wall 12 is formed with an internal circumferential rib 13 adjacent the open end or mouth of the container body 11. To reinforce this region of the container, which is known as the chime, a metal reinforcing ring 15 is provided which reinforces the open end of the container body 11 and maintains the desired shape of the chime. This structure is Well known in the shipping container art, and comprises no part of the present invention.

The shipping container further comprises a cover member indicated generally at 16 which is rnade of iibrous, nonemetallic material. The cover is made up of two parts, an outer layer element 17 and an inner layer element 18. The outer element 17 in the embodiment of FIG. 1 consists of a substantially flat disk-shaped portion 20 surrounded by a circumferential step or convolution 21 and an annular area 22 which meets a downturned rim or flan-ge 23. The latter element is formed as a downturned edge which slips over and engages the mouth of the container body 11. The cover 16 may be secured to the container body 11 in any suitable manner; for exampleJby a split clamping ring 25 which opens at a piont (not shown) along its periphery `so that it may be slipped over the rim 23 and clamped tight against the chime to secure the cover 16 in place.

According to a principal aspect of the invention, the inner layer element 18 of the cover 16 is formed as a separate member which bears against the internal circumferential rib 13 to effect a seal in that region. This is accomplished by providing the inner layer member 18 with a resilient peripheral lip or ange 26 which is resiliently pressed against the internal rib 13 when the lid 16 is clamped into place. Before assembly, the free distance from the outer periphery of the lip 26 to the outer member flange area 22 is `greater than the depth of the internal rib 13 from the mouth of the container body 11, so that the lip is resiliently deflected when assembled. In the embodiment illustrated in FIG. 1, the peripheral edge of the lip 26 is caused to be spaced away from the ange area of the outer layer element 17 by the circumferential step 21 which acts as an annular or reinforcement member. The inner layer element 18 is initially formed with an upstanding lip 26 which is somewhat resilient due to the natural resiliency of the fibrous material itself. However, this resiliency is considerably enhanced by the nesting of the inner layer member 18 within the corresponding depression caused by the circumferential step 21 in the outer layer member 17. In this Way the inner periphery of the lip 26 is doubly supported against bending, and the natural resiliency of the lip is considerably enhanced as a result.

It has been observed that the lip or flange 26 of the inner layer element 18 occasionally has the inclination to resume its original flat form, and thus to decrease or eli-minate the spacing between its upper periphery and the flanged area 22 of the outer layer 17. This is particularly true when the inner layer 18 is made of paperboard or the like which might be exposed to moisture. As a result, the lip 26 may disengage from the rib 13, thereby irnpairing the efficiency of that seal. For this reason the circumferential step 21 is formed so that the step serves as an annular spacer element to preserve the resilience and spacing of the lip 26 relative to the flange area 22 of the outer layer 17. This construction has the additional advantage of providing good drainage qualities to the top of the container, and providing or promoting the stacking of one individual container upon another through the formation of a mating surface formed on the Ibottom of the containers (not shown).

As a result, it may be seen that the central portion of the outer layer 17 is reinforced by a corresponding portion of the inner layer 18, while only the single thickness of the outer layer in the region of the flange area 22 needs to be deformed to form the rim or skirt 23. It should be also appreciated that although the embodiments described herein incorporate elements 17, 18 which are advantageously made of fibrous material such as paperboard, either or both of them may also be made of a suitable plastic material, or of metal. Such constructions also enjoy the advantages afforded by the present invention.

When applied to a container body 11, the lip 26 is pressed against the upper surface of the inner rib 13 by the clamping action of the clamping ring as it is contracted through a suitable clamping or contracting means (not shown). This accomplishes the purpose of sealing the container in two areas, both along the mouth of the container adjacent the metal reinforcing ring 15, and along the upper surface of the inner rib 13 through the action of the resilent lip 26. As a result, a double seal is obtained and the contents of the container are also prevented from coming into contact with the metal reinforcing ring 15.

The features of the invention may also be incorporated in alternative embodiments. In the embodiment illustrated in FIG. 2, a separate supporting ring 30 is added which additionally enhances the resilient qualities of the lip or ange 26. The supporting ring 30 is made in annular form CII from rubber, plastic or other resilient material, and is positioned in the gap between the lip 26 and the flange area 22 of the outer element 17 so as to provide a slight wedging action. The sealing effect, however, is the same as that of the circumferential step 21 in the embodiment illustrated in FIG. 1.

As may be seen from FIGS. 1 and 2, the free outer diameter of the deflected portion of the lip 26 may be made equal or even slightly greater than the inner diameter of the container body 11 adjacent the internal rib 13. In this way the thinouter edge of the lip 26 when in place will be clenched and pressed tightly against the container wall 12 above the internal rib 13, thus enhancing the sealing properties of the closure.

In FIG. 3, another alternative embodiment is shown. In this case the circumferential step 21 of the preceding embodiments is omitted, and the annular support element consists solely of an independent supporting ring 31 as shown. In this embodiment, the layer element 18 is preferably bonded by gluing or similar means to the outer layer element to prevent the wedging action of the supporting ring 41 from separating the two elements 17, 18 from their region of contact at their centers. This construction may be preferred when the containers are to be handled by means of pallets, rather than being stacked.

In a further embodiment, shown in FIG. 4, the outer layer element 17 is formed with a separate convolution 32 which substantially duplicates the supporting function of the circumferential step 21 of the embodiment of FIG. 1, but in a different way, The convolution 32 is formed at a radius such that a circumferential supporting rib 33 is formed at a point corresponding to the position of the supporting rings 30, 31 in the embodiments illustrated in FIGS. 2 and 3. This rib 33 therefore engages the lip 26 at a point spaced from its innermost diameter, and therefore is able to increase the stiffness and resilience of the lip 26 because of the greater leverage available at this point. The convolution 32 which appears on the exterior of the cover 16 also promotes stacking if the bottom of the container (not shown) is formed with a corresponding surface. This construction does not have a central upraised portion as in the embodiments of FIGS. 1 and 2, and therefore lends itself to handling by means of pallets.

In all of the embodiments described herein, the preferred construction contemplates that the inner and outer layer elements 17, 18 shall be secured in their central portion by an adhesive or other suitable means. Alternatively they may comprise separate parts loosely placed on top of one another, although certain advantages of stiffness and strength may be lost in some degree thereby.

The following is claimed as invention:

1. In a shipping container having a body with an open end, said body having an internal circumferential rib adjacent the open end, an improved cover assembly comprising an outer layer element and an inner layer element, said outer layer element having a central portion and a circumferential flange portion adapted to surround the open end of said body, and said inner layer element having a central portion engaging the central portion of said outer layer element and a resilient circumferential lip having a diameter greater than the internal diameter of said internal circumferential rib, and said lip having a periphery which is spaced from said outer layer element by a free distance greater than the axial distance from the end opening of said body to said circumferential internal rib, whereby a seal is effected upon the engagement of said cover and body through the resilient deflection of said lip against said circumferential internal rib.

2. A cover assembly as defined in claim 1 in which the free outer diameter of said lip when assembled against said internal rib is greater than the inner diameter of the open end of said body, whereby said lip is clenched against said inner diameter.

3. A cover assembly as defined in claim 1 which includes an annular support element between said external layer element and said lip, said support element being spaced inwardly from the outer periphery of said lip.

4. A cover assembly as defined in claim 3 wherein said annular support element ,comprises an annular ridge formed in said louter layer element and disposed in supporting relationship to said lip.

5. A cover assembly as defined in claim 3 wherein said annular support element consists of an annular internal ridge Iormed in said outer layer element and disposed in supporting relationship to said lip at a point spaced from the inner diameter of said lip.

6. A cover assembly as defined in claim 3 wherein saidV annular support element comprises a separate ring interposed between said outer layer element and said lip.

References Cited UNITED STATES PATENTS 2,391,774 12/1945 Eggerss 229-5.7X 3,186,620. 6/1965 Meijers 229-5] DAVID M. BOCKENEK, Primary Examiner. 

